Air batteries are capable of containing a higher proportion of the negative electrode active material in the battery case, in comparison with such as lithium secondary batteries. Therefore, they are capable of obtaining a higher discharge capacity, which means that size reduction and weight reduction of the batteries are easier. Moreover, the air batteries have a low environmental impact because they use oxygen, which is free from constraints on resource availability and also is a clean material, as the positive electrode active material. For these reasons, it is expected that the air batteries will be widely used for such as batteries for electric vehicles, batteries for hybrid vehicles, and batteries for fuel cell vehicles.
Here, it is required that the positive electrode for the air battery have electrical conductivity, chemical stability, and capability of supplying oxygen-originating hydroxide ions. In view of this, a positive electrode for an air battery that has a catalyst layer formed by adding activated carbon and a catalyst to Teflon (registered trademark) (Patent Literature 1) and a positive electrode for an air battery that uses a carbon material that permeates gas but does not permeate liquid (Patent Literature 2) have been disclosed.